Calla lilies have beautiful, trumpet-shaped flowers over two-inches wide at the mouth. Their attractive appearance has made them popular in gardens for centuries, after being introduced into Europe from tropical Africa. Unfortunately, their African origins have rendered them unsuitable for leaving in the ground outside over the winter in zones north of zone 7. However, if you do happen to live in zone 6 or farther north, you can still grow them outside. You’ll just have to dig them up before winter comes.
Calla Lilies need very little care, but soil that is too wet creates problems. If your lily rhizomes rot or the leaves turn yellow, improve the drainage by digging a hole about 6 inches across and 6 inches deep, mixing the dirt from the hole with an equal volume of peat moss and refilling it before replanting the rhizome.
Grow callas from seed. At the end of each season, you’ll notice what looks like a cluster of green beads. Remove the "beads" at the end of each growing season and next season, when the soil has warmed up to about 70 degrees, place them in the ground about ½ inch deep. They’ll sprout in about one to three months, and they should be flowering after about three years.
Callas make great cut flowers for flower arrangements.